As the coating material, powdered material is preferably used, but liquid coating material can also be used. In electrostatic spray-coating, the coating material is electrostatically charged by means of high-voltage electrodes, in a known manner, either directly before or after being atomized. The high-voltage electrodes are connected to a high voltage generator, which generates a high voltage, for example of 100 kV. However, other voltages in the range from 30 to 140 kV are also known.
Comparable electrostatic spray devices are known, for example, from U.S. Pat. No. 4,993,645 and U.S. Pat. No. 5,022,590. They show a spray gun with a gun barrel and a holder, which latter can be a handle or an element which can be attached to a holder device, such as a robot, for example. The gun barrel and the carrier or holder are connected with each other so that they can be released, and are structured in such a way that the same gun barrel can be optionally attached to a gun handle or a carrier or holder device which can be attached to a robot. The gun barrel and the carrier are connected with each other so that they can be released, by means of a plug-in connection, and they are structured in such a way that when they are plugged together, fluid lines and electrical lines which pass through them are also connected with each other at the same time.
Furthermore, it is known from the state of the art to attach several electrostatic spray-coating guns to a lifting device by means of their carriers, and to coat an object with them at the same time. The use of several spray guns instead of a single spray gun makes it possible to spray a thicker layer of coating material onto an object, while it is moved past the spray guns in a single pass, than would be possible when using only a single spray gun. Particularly when spray-coating objects with powder, it is not possible to spray any desired amount of powder onto the object per time unit, because the powder velocity required for a higher amount of powder and a correspondingly large number of powder particles which strike the object at the same time have the result that many powder particles bounce off the object again instead of adhering to it. Furthermore, the quality of the coating to be produced can be impaired in this connection.